Problem 1: when I build>add object into scene mode at frame 5, it also appears on all prior frames, something I do not want.Problem 2: when I edit>hide a selected object, it disappears on prior frames, something I do not want.Problem 3: when I edit>delete elements a selected object, is is deleted on prior frames, something I do not want.Problem 4: when I build>add object, then move an existing object to behind the camera, it tweens to move between the two points, something I do not want(I want it to disappear discretely, not move away at linear velocity).

How can I get this done?

Thanks ahead of time.

PS: I found one way to do it by having every object on every frame, but modifying the visibility on each critical frame:

Is this the only way to accomplish this? because I imagine having 1000+ objects(number of morphing objects * average number of discrete morph steps of each object, eg 3 balls, 10 variations of each ball means 30 objects in each frame) in each frame be problematic.

You need to use the Visibility controller. Double click on an object and in the properties dialog click the "..." button next to "Visible" in the Other Animated Properties section. Then click "Add Key" set the value to 1 to show the object and 0 to hide it. It will be shown//hidden from this frame until the next frame that a key is set with a different value. You can also edit the controller in the track window.

The Edit->Hide command is an editing command that allows you to temporarily hide things that are in the way of your work. The Edit->Delete command deletes things from your project.

Problem 4:

The easiest way to do this is to make two keys in the frames before (i.e. 10) and after (i.e. 11) where you want the object to move. Set them to "Corner" in the key properties dialog, and THEN in frame 11 move the object (with animation enabled).

You can also do this with Step keys but you may need to adjust the entering and exiting directions in the Graph Editor to keep your object stable.